{
  "bibcode": "2018GCN.23011....1F",
  "body": "D. Frederiks, S. Golenetskii, R.Aptekar, A. Kozlova,\nA.Lysenko,  D. Svinkin, A. Tsvetkova,  M. Ulanov, and T. Cline,\non behalf of the Konus-Wind team, report:\n\nThe long, extremely bright GRB 180720B\n(Swift-BAT detection: Siegel et al., GCN 22973, GCN 22975;\nFermi-LAT detection: Bissaldi and Racusin, GCN 22980;\nFermi-GBM detection: Roberts et al., GCN 22981)\ntriggered Konus-Wind at T0=51705.261 s UT (14:21:45.261).\n\nThe burst light curve shows a multi-peaked structure\nwith a total duration (T100) of ~125 s.\nThe emission is seen up to ~15 MeV.\n\nAs observed by Konus-Wind, the burst had a fluence of\n(5.43 �� 0.26)x10^-4 erg/cm2 and a 64-ms peak energy flux,\nmeasured from T0+15.168, of (9.70 �� 0.52)x10^-5 erg/cm2\n(both in the 20 keV - 10 MeV energy range).\n\nThe time-integrated spectrum (measured from T0 to T0+119.808 s)\nis best fit in the 20 keV - 15 MeV range\nby the GRB (Band) function with the following model parameters:\nthe low-energy photon index alpha = -1.01 (-0.06,+0.06),\nthe high energy photon index beta = -2.07 (-0.08,+0.07),\nthe peak energy Ep = 451 (-45,+52) keV,\nchi2 = 102/97 dof.\n\nThe spectrum near the peak count rate (measured from T0+14.592 s\nto T0+15.360 s) is best fit in the 20 keV - 15 MeV range\nby the GRB (Band) function with the following model parameters:\nthe low-energy photon index alpha = -0.82 (-0.09,+0.10),\nthe high energy photon index beta = -2.27 (-0.22,+0.13),\nthe peak energy Ep = 779 (-127,+169) keV,\nchi2 = 92/76 dof.\n\nAssuming the redshift z=0.654 (Vreeswijk et al., GCN 22996)\nand a standard cosmology model with H_0 = 70 km/s/Mpc,\nOmega_M = 0.30, and Omega_Lambda = 0.70,\nwe estimate the following rest-frame parameters:\nthe isotropic energy release E_iso is ~6.0x10^53 erg,\nthe peak luminosity L_iso is ~1.8x10^53 erg/s,\nand the rest-frame peak energy of the time-integrated spectrum,\nEp,z, is ~746 keV.\n\nThe Konus-Wind light curve of this GRB is available at\nhttp://www.ioffe.ru/LEA/GRBs/GRB180720_T51705/\n\nAll the quoted errors are estimated at the 90% confidence level.\nAll the presented results are preliminary.",
  "circularId": 23011,
  "createdOn": 1532267019000,
  "email": "fred@mail.ioffe.ru",
  "subject": "Konus-Wind observation of GRB 180720B",
  "submitter": "Dmitry Frederiks at Ioffe Institute  <fred@mail.ioffe.ru>",
  "eventId": "GRB 180720B"
}